In general, two heating methods are adopted in joint residential complexes such as apartment complexes; for example, one is an individual heating method in which an individual heater is used for each household, and the other is a central heating method in which hot water for heating and living uses is supplied from a center control.
The heating method of the heat demander, that is, apartment complexes, which adopts the centralized type heating method, is performed by heating water using fuel such as B-C oil, LNG, LPG, or the like, and intermittently providing heated water or vapor of 100° C. or higher as hot water to each household in the apartment complex 3 to 5 times a day.
In this centralized type heating method in the related art, because water or vapor is produced in a boiler, and the produced vapor is heat exchanged to high temperature water by a heat exchanger so as to be provided as hot water, it can be seen that a large number of boilers are used, and the heat exchange method, which exchanges vapor for hot water, causes a large amount of heat loss.
As a method for resolving the aforementioned drawback, a combined heat and power system having high efficiency energy use is suggested as an alternative.
The combined heat and power system is a total energy system that simultaneously produces electric power and heat from a single energy source, and generally operates an energy system in which a high temperature part is used as power, and a low temperature part is used as heat.
Among the combined heat and power systems, as illustrated in FIG. 1, a widely used type of combined heat and power system that is distributed for domestic use is configured to store heat subordinately generated from a power unit 10 in a heat-storage tank 12, and provide heat by heating using a boiler 14 when heat is required.
However, because the disclosed widely used combined heat and power system is configured so that waste heat of the power unit 10 is directly heat exchanged inside the heat-storage tank 12, it is difficult to dispose the system efficiently, and in addition, because an amount of heat is varied in accordance with a capacity of the power unit 10, pipes of a heat exchange part, which will be installed inside the heat-storage tank 12, need to be designed to have different diameters for each capacity of the power unit 10, and thereby versatility deteriorates, and there are many difficulties in terms of development.
In addition, the boiler 14, which is subsidiarily driven for an insufficient amount of heat to heat heating water or hot water, is formed in a structure provided with a burner 14a that is a heat source, a heat exchanger 14b configured to transfer heat of the burner 14a to heating water and/or hot water, and an expansion tank 14c configured to supplement water into heating piping or adjust pressure of the heating piping, but although the expansion tank 14c may be shared because the expansion tank 14 may perform a function similar to that of the heat-storage tank 12, the expansion tank 14c needs to be separately designed, so that there are drawbacks in that costs and energy are wasted.
Moreover, because the heat-storage tank 12 is formed in a hermetic structure in which piping performing a heat exchange function to produce hot water is installed, a shape of the heat-storage tank 12 is limited to a cylindrical shape for safety against internal pressure, and hereby, because there are many dead zones (dead spaces), an installation space may not be efficiently used, a volume is increased, a structure is complicated, and it is difficult to change the structure after design.